Graphene-Based Threads, Fibers or Yarns with Nth-Order Layers and Twisting and Methods of Fabricating Same

ABSTRACT

A representative embodiment includes a graphene-based fiber comprising: a starting strand; and a plurality of coatings of aligned graphene comprising: a first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand. Another embodiment includes a plurality of intertwined and twisted graphene-based fibers. In various embodiments, the graphene may be graphene ribbons or carbon nanotubes or both. The graphene ribbon includes a plurality of aligned and overlapping graphene flakes in a polymer. Methods of fabrication are also disclosed.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a nonprovisional and conversion of and, under 35 U.S.C. Section 119, claims the benefit of and priority to U.S. Provisional Patent Application No. 61/683,101, filed Aug. 14, 2012, inventor William Johnstone Ray, entitled “Carbon Nanotube-Based Thread or Fiber with Nth-Order Multi-Tube Layers, Twisting and Chirality and Method of Fabricating Same”, which is commonly assigned herewith, the entire contents of which are incorporated herein by reference with the same full force and effect as if set forth in their entirety herein, and with priority claimed for all commonly disclosed subject matter.

FIELD OF THE INVENTION

The present invention in general is related to threads and fibers utilized to produce high tensile strength materials and, in particular, is related to a carbon nanotube and other graphene-based threads or fibers with nth-order layers, twisting and chirality and methods of fabricating carbon nanotube or other graphene-based threads or fibers with nth-order layers, twisting and chirality.

BACKGROUND OF THE INVENTION

Both single walled carbon nanotubes (SWCNTs) (as a type of carbon nanotube (“CNT”)) and other forms of graphene offer several interesting properties, one of which is extreme tensile strength. A single SWCNT theoretically offers a measured strength of something on the order of over 60 GPa. To put this in perspective 60 GPa, or 60 billion Pascals, represents 60,000 million Pascals, and each million Pascal represents about 28,000 foot pounds of strength. It is also recognized that the carbon-carbon bond is one of the strongest found in nature and that the calculated ideal strength of graphene is actually less than its measured strength.

However, neither SWCNTs nor graphene flakes have yet to be made in practical macro-scale lengths. Furthermore, if many micron length SWCNTs or graphene flakes are assembled into a composite material, the strength is significantly diminished, e.g., by several orders of magnitude, due to poor load transfer efficiency between whatever matrix the carbon materials are housed in and the graphene flakes or SWCNTs themselves.

This limited interfacial strength between CNTs and their polymer matrix has been noted in scientific literature to be due to the atomically smooth surfaces of the CNTs allowing slippage between CNTs and matrix polymers due to the fact that there is no covalent bonding between the matrix and the CNTs. While this potentially could be mitigated by chemically modifying the CNT in some way, such modifications are generally undesirable because such modification generally dramatically decreases CNT tensile strength due to tube defects derived from such treatment.

Accordingly, a need remains for a carbon nanotube or other graphene-based thread or fiber which is capable of maintaining its tensile strength, despite the existing limitations in producing macro-scale SWCNTs and graphene flakes of any significant length. Such carbon nanotube or other graphene-based thread or fiber should also be capable of being readily produced on a large scale for any of various practical applications in which a comparatively high tensile strength is necessary or desirable.

SUMMARY

The exemplary embodiments provide a graphene (or graphene-based) thread or fiber with nth-order layers, twisting and chirality and methods of fabricating a graphene (or graphene-based) thread or fiber with nth-order layers, twisting and chirality. For example, a representative embodiment provides a graphene (or graphene-based) thread or fiber comprised of a plurality of nth-order, wound or twisted graphene ribbons, with nth-order layers, twisting and chirality. Each graphene ribbon comprises, in turn, a plurality of substantially aligned (and overlapping) graphene flakes in a polymer on a substrate. Also for example, other representative embodiments provide a carbon nanotube-based thread or fiber with nth-order multi-tube layers, twisting and chirality. Representative embodiments further include methods of fabricating a graphene (or graphene-based) thread or fiber with nth-order layers, twisting and chirality.

For purposes of the present disclosure, CNTs (such as SWCNTs) are viewed as a tubular form of the more general or generic graphene structure, namely, a pure, rolled up graphene sheet. As a consequence, any reference to a graphene (or graphene-based) thread or fiber or to another graphene-based structure should be understood to mean and include such single walled (or multi-walled) carbon nanotubes and other forms of graphene and/or CNTs as species of the more generic graphene-based structures. Similarly, while use of single walled carbon nanotubes are illustrated, it should be understood that the present disclosure is not limited to such single walled CNTs, and other graphene-based tubular structures are also within the scope of the disclosure, such as multi-walled CNTs.

A first exemplary embodiment provides a graphene-based fiber comprising: a starting strand; and a plurality of coatings of aligned graphene comprising: a first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.

In various exemplary embodiments, the graphene comprises at least one graphene ribbon. The at least one graphene ribbon may comprise a plurality of aligned and overlapping graphene flakes in a polymer. In another exemplary embodiment, the at least one graphene ribbon may comprise a plurality of aligned and overlapping graphene flakes in a polymer and on a substrate. The plurality of coatings may further comprise a plurality of winding layers of a plurality of the graphene ribbons.

In another exemplary embodiment, the graphene comprises a plurality of carbon nanotubes in a polymer. The carbon nanotubes may further comprise a metallic chirality or a semiconducting chirality. In such an exemplary embodiment, the first angle may be about 0°, the second angle may be about 45°, and the at least one next angle may comprise a third angle of about 135° and a fourth angle of about 90°.

In various exemplary embodiments, the starting strand comprises a metal, or a polymer, or a combination of a metal and a polymer.

Also in various exemplary embodiments, the first coating further comprises a first twist direction of the aligned graphene, the second coating further comprises a second, opposite twist direction of the aligned graphene, and the at least one next coating further comprises the first or the second twist direction of the aligned graphene.

A representative graphene-based yarn is also disclosed, comprising: a plurality of intertwined and twisted graphene-based fibers, each graphene-based fiber of the plurality of intertwined and twisted graphene-based fibers comprising: a starting strand; and a plurality of coatings of aligned graphene comprising: a first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.

A representative method of manufacturing a graphene-based yarn is also disclosed, the method comprising: using a starting strand, applying first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; applying a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and applying at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.

In various exemplary embodiments, the graphene comprises a plurality of graphene ribbons and the application steps further comprise winding or spinning a plurality of layers of the plurality of graphene ribbons. In such exemplary embodiments, each graphene ribbon of the plurality of graphene ribbons comprises a plurality of aligned and overlapping graphene flakes in a polymer. Such an exemplary method of manufacturing a graphene-based yarn may further comprise forming the plurality of graphene ribbons by applying, using a shearing force, the plurality of graphene flakes in the polymer onto a substrate.

Another exemplary method embodiment provides cutting the substrate having the plurality of graphene flakes in the polymer into a plurality of strips; and winding the plurality of strips onto one or more reels. Such an exemplary method embodiment may further provide removing the substrate to form the plurality of graphene ribbons; and winding or spinning the plurality of graphene ribbons.

In various exemplary method embodiments, the graphene may comprise a plurality of carbon nanotubes in a polymer. In such exemplary embodiments, the application steps may further comprise: orienting the carbon nanotubes using an applied electromagnetic field; for example, the electromagnetic field is applied at the first angle of about 0°, the electromagnetic field is applied at the second angle of about 45°, and the electromagnetic field is applied at the least one next angle comprising a third angle of about 135° and a fourth angle of about 90°.

The various exemplary method embodiments may further comprise: applying the first coating using a first twist direction of the aligned graphene; applying the second coating using a second, opposite twist direction of the aligned graphene; and applying the at least one next coating using the first or the second twist direction of the aligned graphene.

The various exemplary method embodiments may further comprise: repeating the application steps to form a plurality of graphene-based fibers; twisting and intertwining the plurality of graphene-based fibers to form a plurality of next-order graphene-based fibers; and twisting and intertwining the plurality of next-order graphene-based fibers to form a graphene-based yarn.

Another exemplary embodiment further comprises a method of manufacturing a graphene-based yarn, the method comprising: using a starting strand and a plurality of graphene ribbons, applying first coating of aligned graphene by spinning a first graphene ribbon, of the plurality of graphene ribbons, about a starting strand at a first angle axially offset from an axis of the starting strand, each graphene ribbon of the plurality of graphene ribbons comprising a plurality of aligned and overlapping graphene flakes in a polymer; applying a second coating of aligned graphene by spinning a second graphene ribbon, of the plurality of graphene ribbons, over the first coating at a second angle axially offset from an axis of the starting strand; applying at least one next coating of aligned graphene by spinning a next graphene ribbon, of the plurality of graphene ribbons, over a preceding coating at a next angle axially offset from the axis of the starting strand; repeating the application steps to form a plurality of graphene-based fibers; and twisting and intertwining the plurality of graphene-based fibers to form a plurality of next-order graphene-based fibers; and twisting and intertwining the plurality of next-order graphene-based fibers to form a graphene-based yarn.

Another exemplary embodiment is an article of manufacture having a first polymer strand or thread; a first coating of carbon nanotubes aligned axially with the first polymer strand or thread; and a plurality of additional coatings of aligned carbon nanotubes axially offset from the first polymer strand or thread.

Another exemplary embodiment is an article of manufacture comprising: a first polymer strand or thread; a first set of coatings of carbon nanotubes having a first layer of carbon nanotubes aligned axially with the first polymer strand or thread and a plurality of additional and successive layers of aligned carbon nanotubes axially offset from the first polymer strand or thread; and at least one second set of coatings of carbon nanotubes layered over the first set of coatings, the at least one second set of coatings having a next layer of carbon nanotubes aligned axially with the first polymer strand or thread and a plurality of additional and successive layers of aligned carbon nanotubes axially offset from the first polymer strand or thread.

In various exemplary embodiments, the article of manufacture may utilize carbon nanotubes which further comprise composite or complex CNT threads having threads or strands of twisted or intertwined CNTs.

Another exemplary embodiment provides a method of manufacturing a carbon nanotube-based thread or fiber with nth-order multi-tube layers, twisting and chirality, the method comprising: using an applied electromagnetic field, aligning a first coating of carbon nanotubes in a first, axial direction of a first polymer strand or thread; and using an applied electromagnetic field, aligning a plurality of additional coatings of carbon nanotubes in a one or more second directions axially offset from the first polymer strand or thread.

Another exemplary embodiment provides a method of manufacturing a carbon nanotube-based thread or fiber with nth-order multi-tube layers, twisting and chirality, the method comprising: using an applied electromagnetic field, aligning a first coating of carbon nanotubes in a first, axial direction of a first polymer strand or thread; using an applied electromagnetic field, aligning a first plurality of additional coatings of carbon nanotubes in a one or more second directions axially offset from the first polymer strand or thread to form a first set of coatings of carbon nanotubes; and using an applied electromagnetic field, aligning at least one second plurality of additional coatings of carbon nanotubes layered over the first set of coatings and aligned in one or more second directions axially offset from the first polymer strand or thread to form at least one second set of coatings of carbon nanotubes.

Another exemplary embodiment further comprises, prior to the alignment steps: twisting or intertwining the carbon nanotubes to form composite or complex CNT threads having threads or strands of twisted or intertwined CNTs.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention will be more readily appreciated upon reference to the following disclosure when considered in conjunction with the accompanying drawings, wherein like reference numerals are used to identify identical components in the various views, and wherein reference numerals with alphabetic characters are utilized to identify additional types, instantiations or variations of a selected component embodiment in the various views, in which:

FIG. 1 is a perspective view illustrating an atomic-level model of a graphene flake.

FIG. 2 is an illustration of an atomic-level model of a comparatively high aspect ratio graphene flake.

FIG. 3 is a perspective view illustrating an exemplary starting strand.

FIG. 4 is a perspective view illustrating the exemplary starting strand with a first layer of axially aligned carbon nanotubes.

FIG. 5 is a perspective view illustrating the exemplary starting strand with a first layer of axially aligned carbon nanotubes and with a second layer of aligned carbon nanotubes axially-offset at a first angle.

FIG. 6 is a perspective view illustrating the exemplary starting strand with a first layer of axially aligned carbon nanotubes, with a second layer of aligned carbon nanotubes axially-offset at a first angle, and with a third layer of aligned carbon nanotubes axially-offset at a second angle.

FIG. 7 is a perspective view illustrating the exemplary starting strand with a first layer of axially aligned carbon nanotubes, with a second layer of aligned carbon nanotubes axially-offset at a first angle, with a third layer of aligned carbon nanotubes axially-offset at a second angle, and with a fourth layer of aligned carbon nanotubes axially-offset at a third angle.

FIG. 8 is a cross-sectional view illustrating the exemplary starting strand with a first layer of axially aligned carbon nanotubes, with a second layer of aligned carbon nanotubes axially-offset at a first angle, with a third layer of aligned carbon nanotubes axially-offset at a second angle, and with a fourth layer of aligned carbon nanotubes axially-offset at a third angle, as a first set of coatings forming a first-order graphene (or graphene-based) thread or fiber.

FIG. 9 is a cross-sectional view illustrating multiple sets of aligned carbon nanotube coatings forming a first embodiment of a second-order graphene (or graphene-based) thread or fiber.

FIG. 10 is a top view illustrating a plurality of graphene ribbons comprised of aligned graphene flakes in a polymer on a substrate.

FIG. 11A is a perspective view illustrating the exemplary starting strand with a first layer of graphene ribbons 200 axially-offset at a first angle.

FIG. 11B is a perspective view illustrating the exemplary starting strand with multiple, successive layers of graphene ribbons 200 axially-offset at correspondingly successive angles to form another embodiment of a graphene (or graphene-based) thread or fiber.

FIG. 12 is an illustration at the level of graphene flakes of multiple, successive layers of graphene ribbons 200 axially-offset at correspondingly successive angles.

FIG. 13 is a perspective view illustrating a second embodiment of a second-order graphene (or graphene-based) thread or fiber comprising multiple threads or strands having multiple sets of aligned carbon nanotube or other graphene-based coatings.

FIG. 14 is a perspective view illustrating a next-order graphene (or graphene-based) thread or fiber comprising multiple threads or strands of lower-order graphene (or graphene-based) fibers, threads or strands having multiple sets of graphene ribbons, aligned carbon nanotube or other graphene-based coatings.

FIG. 15 is a flow diagram illustrating a method of fabricating a graphene (or graphene-based) thread or fiber with nth-order layers, twisting and chirality.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

While the present invention is susceptible of embodiment in many different forms, there are shown in the drawings and will be described herein in detail specific exemplary embodiments thereof, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. In this respect, before explaining at least one embodiment consistent with the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of components set forth above and below, illustrated in the drawings, or as described in the examples. Methods and apparatuses consistent with the present invention are capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purposes of description and should not be regarded as limiting.

FIG. 1 is a perspective view illustrating an atomic-level model of a graphene flake 100. FIG. 2 is an illustration of an atomic-level model of a comparatively high aspect ratio graphene flake 100. Such one or two carbon layer flakes 100 (effectively a “two dimensional” material as the thickness is in the angstrom range) demonstrate very similar structural characteristics to the SWCNT. High aspect ratio graphene flakes (e.g., >1, ≧2:1, ≧3:1, ≧4:1, ≧5:1, etc.), such as those illustrated in FIG. 2 and in FIG. 10 and as discussed in greater detail below, may be printed in multi-micron wide ribbons using a mechanical approach in which anisotropic thin films may be produced by a shear oriented assembly of graphene flakes and/or CNTs, similarly to colloidal nanorods.

As discussed in greater detail below, the present disclosure concerns graphene (i.e., graphene-based) threads or fibers (150, 175, 250, 225, 275), which may be comprised of graphene ribbons 200, or CNTs 110, and/or a combination of both graphene ribbons 200 and CNTs 110. The graphene ribbons 200, in turn, are comprised of substantially aligned (and overlapping) graphene flakes (or platelets) 100 in a polymer 190 disposed on a substrate 195. Also as mentioned above, for purposes of the present disclosure, CNTs 110 (such as SWCNTs) are viewed as a tubular form of the more general or generic graphene structure, namely, a pure, rolled up graphene sheet. As a consequence, any reference to a graphene (or graphene-based) thread or fiber (150, 175, 250, 225, 275) or to another graphene-based structure should be understood to mean and include such single walled (or multi-walled) carbon nanotubes and other forms of graphene and/or CNTs as species of the more generic graphene-based structures. Similarly, while use of single walled carbon nanotubes are illustrated, it should be understood that the present disclosure is not limited to such single walled CNTs, and other graphene-based tubular structures are also within the scope of the disclosure, such as multi-walled CNTs.

Several embodiments of a graphene (or graphene-based) thread or fiber (150, 175, 250, 225, 275) are illustrated. Those having skill in the art will recognize that additional variations and combinations are available based on the present disclosure, and all such variations and combinations are considered equivalent and within the scope of the disclosure.

Consider a thread type structure of length X. Let us assume that this thread is built from a mixture of an appropriate polymer mixed with SWCNTs that are aligned with the polymer. The strength in the X direction of this thread on a “CNT fragment” basis would be very great, indeed, were it not for the fact that the junction points between CNTs can only be the strength of the polymer mitigated by the “fasces” effect of the CNTs, as mentioned above, and would not provide anything close to the tensile strength of the various representative embodiments of this disclosure.

FIG. 3 is a perspective view illustrating an exemplary starting strand 105. Such a starting strand 105 may be comprised of any suitable material, such as any metal, a carbon fiber, or a polymer, for example and without limitation. Such a starting strand 105 typically has a high-aspect ratio, and it typically long and thin, like a typical fabric thread, also for example and without limitation. For example, the starting strand 105 may comprise at least one metal selected from the group consisting of: steel, iron, aluminum, copper, silver, gold, nickel, palladium, tin, platinum, lead, zinc, alloys thereof, and mixtures thereof, including various forms of carbon-based steel. Also for example, the starting strand 105 may comprise any type of polymer-based or carbon-based fiber, such as a para-aramid (e.g., poly-paraphenylene terephthalamide (Kevlar®)) synthetic fiber. Also for example and without limitation, the starting strand 105 may comprise any polymer, polymeric precursor, resin or binder, such as those selected from the group consisting of: polymers such as polyvinyl pyrrolidone, polyvinyl alcohol, polyimide polymers and copolymers (including aliphatic, aromatic and semi-aromatic polyimides), acrylate and (meth)acrylate polymers and copolymers; glycols such as ethylene glycols, diethylene glycol, polyethylene glycols, propylene glycols, dipropylene glycols, glycol ethers, glycol ether acetates; possibly clays such as hectorite clays, garamite clays, organo-modified clays; possibly saccharides and polysaccharides such as guar gum, xanthan gum; celluloses and modified celluloses such as hydroxy methylcellulose, methylcellulose, ethyl cellulose, propyl methylcellulose, methoxy cellulose, methoxy methylcellulose, methoxy propyl methylcellulose, hydroxy propyl methylcellulose, carboxy methylcellulose, hydroxy ethylcellulose, ethyl hydroxyl ethylcellulose, cellulose ether, cellulose ethyl ether, chitosan; possibly fumed silica, silica powders, modified ureas; and mixtures thereof.

Essentially, the starting strand 105 may comprise any material capable of supporting applications or windings of either CNTs 110 or graphene ribbons 200. For example and without limitation, a starting strand may comprise one or more graphene ribbons. In other various embodiments, the starting strand 105 may also be removed following such applications or windings.

It should also be noted that the polymer selected may also be electrically conductive, allowing the carbon nanotube or other graphene-based threads or fibers (150, 175, 250, 225, 275) to be electrically conductive, in addition to having significant tensile strength. For example, conductive inks and/or conductive polymers may be utilized, such as copper, tin, aluminum, gold, noble metals, carbon, carbon black, graphene, graphene flakes, nanographene platelets, nanocarbon and nanocarbon and silver compositions, nano particle and nano fiber silver compositions, other organic or inorganic conductive polymers, inks, gels or other liquid or semi-solid materials. Exemplary conductive compounds include: (1) from Conductive Compounds (Londonberry, N.H., USA), AG-500, AG-800 and AG-510 Silver conductive inks, which may also include an additional coating UV-10065 ultraviolet curable dielectric; (2) from DuPont, 7102 Carbon Conductor, 7105 Carbon Conductor, 5000 Silver Conductor, 7144 Carbon Conductor (with UV Encapsulants), 7152 Carbon Conductor (with 7165 Encapsulant), and 9145 Silver Conductor; (3) from SunPoly, Inc., 128A Silver conductive ink, 129A Silver and Carbon Conductive Ink, 140A Conductive Ink, and 150A Silver Conductive Ink; (4) from Dow Corning, Inc., PI-2000 Series Highly Conductive Silver Ink; (5) from Henkel/Emerson & Cumings, Electrodag 725A; (6) Monarch M120 available from Cabot Corporation of Boston, Mass., USA, for use as a carbon black additive, such as to a silver ink to form a mixture of carbon and silver ink; (7) Acheson 725A conductive silver ink (available from Henkel), alone or in combination with additional silver nanofibers; and (8) Inktek PA-010 or PA-030 nanoparticle or nanofiber silver screen printable conductive ink, available from Inktec. of Gyeonggi-do, Korea. Other conductive polymers may also be utilized, for example and without limitation, include polyaniline and polypyrrole polymers, polyethylene-dioxithiophene (such as the polyethylene-dioxithiophene commercially available under the trade name “Orgacon” from AGFA Corp. of Ridgefield Park, N.J., USA), a combination of poly-3,4-ethylenedioxythiophene and polystyrenesulfonic acid (marketed as Baytron P and available from Bayer AG of Leverkusen, Germany), a polyaniline or polypyrrole polymer, and/or antimony tin oxide (ATO) (with the ATO or others typically suspended as particles in any of the various binders, polymers or carriers).

FIG. 4 is a perspective view illustrating the exemplary starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110. In a representative embodiment, a starting strand 105, such as a thin polymer or wire strand, is bathed or otherwise immersed in a liquid having a plurality of SWCNTs, such as an aqueous mixture of high concentration SWCNTs, typically further having a polymer or other polymeric precursor. An electromagnetic field is applied along the length of the starting strand 105, in the axial direction, resulting in the alignment, to a significant degree, of the SWCNTs in the axial direction, namely, the CNTs aligning end-to-end along the length of the polymer or wire strand, particularly if the CNTs are de-capped and open at both ends (although that is not required). In this instance, the offset from the axial direction is generally or roughly about zero degrees. When graphene ribbons 200 are utilized, the first angular offset from the axial direction is typically greater than zero degrees, as discussed in greater detail below.

It should be noted that the CNTs 110 which may be utilized may have any selected chirality, including metallic (ballistic) and semiconducting, for example and without limitation. This is in addition to any selected twisting (or chirality) of the various components (aligned CNTs 110, graphene ribbons 200) of the graphene (or graphene-based) thread or fiber (150, 175, 250, 225, 275).

The starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 is then cured, such as through a heat or uv curing process, with the polymer or other polymeric precursor forming a matrix embedding the CNTs 110. Alternatively, when the immersion media does not include a polymer or other polymeric precursor, the starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 may be removed from the bath, and the aligned CNTs may be coated with a thin layer of matrix monomer, polymer or other polymeric precursor that can then be polymerized, also such as through a heat, infrared (IR) or ultraviolet (uv) curing process. Locally rigid support to maintain the alignment of such a CNT matrix (or layer) is the only significant role for this polymer layer.

FIG. 5 is a perspective view illustrating the exemplary starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 and with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle. FIG. 6 is a perspective view illustrating the exemplary starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, and with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle. FIG. 7 is a perspective view illustrating the exemplary starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle, and with a fourth layer 130 of aligned carbon nanotubes 110 axially-offset at a third (or next) angle. FIG. 8 is a cross-sectional view illustrating the exemplary starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle, and with a fourth layer 130 of aligned carbon nanotubes 110 axially-offset at a third (or next) angle, as a first set of coatings forming a first-order graphene (or graphene-based) thread or fiber 150. FIG. 9 is a cross-sectional view illustrating multiple sets of aligned carbon nanotube coatings forming an embodiment of a second-order graphene (or graphene-based) thread or fiber 175.

The starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 is then re-immersed in the liquid having the CNTs, and the electromagnetic field is applied at a first (or next) angle (“a”) offset from the axial direction, such as at 45 degrees to the length of the thread, while slowly rotating the starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, clockwise as illustrated (i.e., a first twist or rotational direction). The starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 and with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle is then removed and cured, as discussed above, using either variation, resulting in a starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 and with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, as illustrated in FIG. 5.

This procedure is repeated, but with the electromagnetic field applied at a second (or next) angle (“β”) offset from the axial direction, such as at 135 degrees to the length of the thread (or 45 degrees measured from the other direction), while slowly rotating the starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110 and with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, counter-clockwise as illustrated (i.e., an opposite, second twist or rotational direction). Stated another way, the two layers of aligned, axially offset carbon nanotubes have an opposite twist (or chirality) (thus both a left hand and right hand 45 degree twist). The starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, and with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle is then removed and cured, as discussed above, using either variation, resulting in a starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, and with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle, as illustrated in FIG. 6.

This procedure is repeated again, but with the electromagnetic field applied at a third (or next) angle (“γ”) offset from the axial direction, such as at 90 degrees (or normal) to the length of the growing thread, also while slowly rotating the growing thread having a starting strand 105 with first, second and third layers 115, 120, 125 of aligned carbon nanotubes at the various angles and twists (rotations). This rotation (or twist) may be either clockwise or counter-clockwise. The growing thread that now includes a fourth layer 130 of aligned carbon nanotubes axially-offset at a third (or next) angle is then removed and cured, as discussed above, using either variation, resulting in a starting strand 105 with a first layer 115 of axially aligned carbon nanotubes 110, with a second layer 120 of aligned carbon nanotubes 110 axially-offset at a first (or next) angle, with a third layer 125 of aligned carbon nanotubes 110 axially-offset at a second (or next) angle, and with a fourth layer 130 of aligned carbon nanotubes 110 axially-offset at a third (or next) angle, as illustrated in FIG. 7, and in cross-section in FIG. 8, forming a first-order graphene (or graphene-based) thread or fiber 150.

While the various CNT 110 windings or twists are illustrated as having one layer of CNTs 110 in each of the successive layers 115, 120, 125, and 130, it should be noted that the windings or twists may continue through more than one complete revolution (twist) of the growing thread or fiber, resulting in more than one layer of CNTs 110 in each of the successive layers 115, 120, 125, and 130. Indeed, this is typically the case when graphene ribbons 200 are utilized, as discussed below, allowing multiple layers of graphene ribbon 200 within each successive winding (e.g., layers 205, 210, 215 discussed below).

As discussed in greater detail below, these procedures to build successive layers 115, 120, 125, and 130, having different axial offset angles and having different twists or rotations may be repeated, successively, to create a thread or fiber having the desired tensile strength or to have other desirable properties.

FIG. 8 illustrates a cross-section of a “basic”, first-order graphene (or graphene-based) thread or fiber 150 with the four CNT coatings, as successive layers 115, 120, 125, and 130, having different axial offset angles (e.g., 0°, 45°, 135°, and 90° degree offsets from axial) and having different (clockwise or counter-clockwise) twists or rotations. Considering these four CNT layers a “coating set”, then additional, higher order “N” such coating sets could be applied to the first-order graphene (or graphene-based) thread or fiber 150, in order to achieve added tensile strength, for example.

Such a higher, second-order graphene (or graphene-based) thread or fiber 175 (as a first embodiment) is illustrated in cross-section in FIG. 9, with four additional CNT coatings, as a second set of successive layers 115A, 120A, 125A, and 130A, each also having a different axial offset angle (e.g., 0°, 45°, 135°, and 90° degree offsets from axial) and having different (clockwise or counter-clockwise) twists or rotations, formed using the procedures discussed above, but now as applied over the first-order graphene (or graphene-based) thread or fiber 150, rather than beginning merely with a starting strand 105. Not separately illustrated, this coating process may continue to be repeated, as necessary or desirable, such as to form third, fourth, to Nth-order graphene (or graphene-based) threads or fibers.

This process of formation of an Nth-order graphene (or graphene-based) thread or fiber may utilize forms of carbon other than CNTs 110, such as the graphene ribbons 200 (comprised of graphene flakes 100), and is illustrated in and discussed below with reference to FIGS. 10-12.

FIG. 10 is a top view illustrating a plurality of graphene ribbons 200 comprised of aligned graphene flakes 100 in a polymer 190 on a substrate 195. A plurality of graphene flakes 100 generally having a comparatively high aspect ratio (e.g., ≧2:1, ≧3:1, ≧4:1, ≧5:1, etc.) of length to width, are immersed in a liquid or gel (such as in an aqueous solution or any of the polymers or polymeric precursors discussed above, any of which may be a polymer 190, including conductive polymers, also as discussed above), and then deposited over a substrate 195 to form a plurality of multi-micron wide ribbons 200, using any deposition technology which provides an applied shearing force, such as various forms of printing and coating technologies. Simply put, the applied shearing force during the deposition of the graphene flakes 100 in a liquid or gel (polymer 190) results in the mechanical alignment of the graphene flakes 100, as illustrated. In addition, there is also some to substantial or significant overlapping of the graphene flakes 100 within each ribbon. It should be noted that the graphene ribbons 200 in FIG. 10 are for purposes of illustration, and actual graphene ribbons 200 would typically have a considerably greater density of aligned graphene flakes 100, and considerably more variation in alignment (in the length (or axial) direction of the ribbon) (e.g., ±1%, ±2%, ±5%, ±10%, ±15%, ±30%, etc., up to the desired or selected manufacturing tolerance level). This mechanical (rather than electromagnetic) approach with a shear oriented assembly of graphene flakes 100 (which could also be applied to CNTs 110, and is within the scope of the disclosure), similarly to assembly techniques for colloidal nanorods, produces generally or significantly aligned (and overlapping) graphene flakes 100 in a polymer 190 on a substrate 195, forming graphene ribbons 200 which, in turn, will be utilized to form successive thread or fiber layers to produce graphene (or graphene-based) threads or fibers (250, 275), as discussed above for CNTs 110 and as discussed in greater detail below.

The aspect ratio of the graphene flakes 100 may be selected empirically, based upon the selected liquid or gel (polymer 190), e.g., an aspect ratio greater than 5:1 for a representative embodiment; however, the present disclosure includes as “high” or “comparatively high” any aspect ratio for the graphene flakes 100 having a length greater than width, i.e., any aspect ratio greater than 1.

The choice of a substrate 195 to print or coat on may be based on surface physics, tensile strength, and bending or other deformation characteristics, for example and without limitation. The substrate 195 may be comprised of any of the metals, compounds, or polymers previously discussed for composition of a starting strand 105, such as a woven sheet or bands of Kevlar®, for example and without limitation, and may also be selected to be electrically conductive, also as discussed above. A substrate 195 may be formed from or comprise any suitable material, such as a polymer, plastic, paper, cardboard, or coated paper or cardboard, for example and without limitation. The substrate 195 may comprise any flexible material having the strength to withstand the intended use conditions. In an exemplary embodiment, a substrate 195 may comprise a polyester or plastic sheet, such as a CT-5 or CT-7 five or seven mil polyester (Mylar) sheet treated for print receptiveness and commercially available from MacDermid Autotype, Inc. of MacDermid, Inc. of Denver, Colo., USA, or a Coveme acid treated Mylar, for example. In another exemplary embodiment, a substrate 195 comprises a polyimide film such as Kapton commercially available from DuPont, Inc. of Wilmington Del., USA, also for example. A substrate 195 may comprise, also for example, any one or more of the following: paper, coated paper, plastic coated paper, fiber paper, cardboard, poster paper, poster board, and other paper or wood-based products in any selected form; plastic or polymer materials in any selected form (sheets, film, boards, and so on) as previously mentioned above; natural and synthetic rubber materials and products in any selected form; natural and synthetic fabrics in any selected form, including polymeric nonwovens (carded, meltblown and spunbond nowovens); extruded polyolefinic films, including LDPE films; glass, ceramic, and other silicon or silica-derived materials and products, in any selected form; or any other product, currently existing or created in the future. The substrate 195 may also comprise laminates or other bondings of any of the foregoing materials.

As used herein, “deposition” includes any and all printing, coating, rolling, spraying, layering, sputtering, plating, spin casting (or spin coating), vapor deposition, lamination, affixing and/or other deposition processes, whether impact or non-impact, known in the art. “Printing” includes any and all printing, coating, rolling, spraying, layering, spin coating, lamination and/or affixing processes, whether impact or non-impact, known in the art, and specifically includes, for example and without limitation, screen printing, inkjet printing, electro-optical printing, electroink printing, photoresist and other resist printing, thermal printing, laser jet printing, magnetic printing, pad printing, flexographic printing, hybrid offset lithography, Gravure and other intaglio printing, for example. All such processes are considered deposition processes herein and may be utilized. The exemplary deposition or printing processes do not require significant manufacturing controls or restrictions. No specific temperatures or pressures are required. Some clean room or filtered air may be useful, but potentially at a level consistent with the standards of known printing or other deposition processes. In addition, the various compounds utilized may be contained within various polymers, binders or other dispersion agents which may be heat-cured or dried, air dried under ambient conditions, or IR or uv cured.

The plurality of graphene ribbons 200, comprised of aligned (and overlapping) graphene flakes 100 in a polymer 190 on a substrate 195, may then be slit or otherwise cut and rolled onto corresponding reels. Multiple reels of the graphene ribbons 200 are then used to spin, layer and/or weave the graphene ribbons 200 around a starting strand 105, as illustrated in FIGS. 11A and 11B. In an exemplary embodiment, the starting strand 105 may also be comprised of a plurality of woven or spun graphene ribbons 200, or any of the other materials discussed above.

In additional representative embodiments, the substrate 195 may also be a “donor” substrate: the graphene flakes 100 in a polymer 190 are deposited on a donor substrate 195 using a method that provides a shearing force, such as by a blade (e.g., “doctor” blade) coating method, and cured or allowed to cure. The aligned (and overlapping) graphene flakes 100 in a polymer 190 on a substrate 195 are again cut or slit into graphene ribbons 200 and rolled onto corresponding reels. During the spinning or winding process to form a first-order graphene (or graphene-based) thread or fiber 250 discussed below, the donor substrate 195 is separated from the aligned (and overlapping) graphene flakes 100 in the now cured/dried polymer 190, e.g., peeled off directly in the production line, and only the aligned (and overlapping) graphene flakes 100 in the cured polymer 190 are utilized to form the first-order graphene (or graphene-based) thread or fiber 250. As a consequence, the graphene ribbons 200 may simply comprise aligned (and overlapping) graphene flakes 100 in the polymer 190.

FIG. 11A is a perspective view illustrating the exemplary starting strand 105 with a first layer of graphene ribbons 200 axially-offset at a first angle. FIG. 11B is a perspective view illustrating the exemplary starting strand with multiple, successive layers of graphene ribbons 200 axially-offset at correspondingly successive angles to form a graphene (or graphene-based) thread or fiber 250. The starting strand 105 is wrapped or wound with a first layer 205 of graphene ribbon 200 at a first angle (“a”) offset from the axial direction, such as at 45 degrees to the length of the thread, typically while rotating the starting strand 105, counter-clockwise as illustrated (i.e., a first twist or rotational direction). This procedure is repeated, but with the starting strand 105 having the first layer 205 wrapped or wound with a second layer 210 of graphene ribbon 200 at a second angle (“β”) offset from the axial direction, such as at 135 degrees to the length of the thread (or 45 degrees measured from the other direction), typically while slowly rotating the starting strand 105 having the first layer 205, clockwise as illustrated (i.e., an opposite, second twist or rotational direction).

This procedure is repeated again, but with the starting strand 105 having first and second layers 205, 210 wrapped or wound with a third layer 215 of graphene ribbon 200 applied at a third angle (“γ”) offset from the axial direction, such as at 90 degrees (or normal) to the length of the growing thread, also while slowly rotating the growing thread having a starting strand 105 having first and second layers 205, 210 at the various angles and twists (rotations). This rotation (or twist) may be either clockwise or counter-clockwise. This process may continue to be repeated, with a growing thread that now includes a plurality of layers, as a basic set as described above, but of graphene ribbons 200 axially-offset at correspondingly successive angles, forming a first-order graphene (or graphene-based) thread or fiber 250, illustrated in FIG. 11B, and illustrated in an exploded view of multiple, successive layers of graphene flakes 100 of the graphene ribbons 200 axially-offset at correspondingly successive angles in FIG. 12. It should be noted that FIG. 11 is for purposes of illustration, to show the various layers, and that each of the various layers 205, 210, and 215, and potentially additional layers 220, 230, 235 offset at additional angles (as illustrated in FIG. 12), in practice may and generally will have, within each such layer, many more or higher density windings (or twists) of graphene ribbons 200 than those illustrated. Moreover, in addition to the twisting or winding illustrated, various layers of woven graphene ribbons 200 and combinations of both winding/twisting and woven graphene ribbons 200 may also be utilized, and all such variations are within the scope of the disclosure.

An additional full or partial curing step may also be utilized between each successive winding step at the different angles. For example, the growing thread with successive layers of graphene ribbons 200 may be heated (e.g., partially melted) and re-cured while maintaining the orientation of the aligned (and overlapping) graphene flakes 100, such as to allow more direct contact between the graphene flakes 100 of successive windings, such as illustrated in FIG. 12. The process for forming a first-order graphene (or graphene-based) thread or fiber 250 then becomes: (1) spin; (2) cure; (3) repeat at a “delta” angle, i.e., a change in the angle of application.

The inventive approach uses the polymer only as a curing and holding matrix for CNTs 110 and/or graphene flakes 100, and relies upon a layered architecture with oriented “CNT fragments” or aligned graphene flakes 100 (of different tensile strength vectors) that are self-replicated over N coating sets. The tensile strength of such a fiber can be approximately calculated by Equation (1):

σ_(y)/σ_(f)≈ cos² α[1−k cos ecα)]  (1)

where: σ_(y)/σ_(f) is the ratio of the tensile strength of the composite fiber (or “yarn”) and the tensile strength of the component fibers, k describes the physical properties of the twisted components and the cos² alpha term describes the fraction of the vector of tensile strength ascribed to the fiber element due to the helical twist.

FIG. 13 is a perspective view illustrating a second embodiment of a second-order graphene (or graphene-based) thread or fiber comprising multiple lower-order graphene (or graphene-based) threads or fibers, and is s illustrated using a graphene (or graphene-based) thread or fiber 150 as an example, having multiple sets of aligned carbon nanotube or other graphene-based coatings. As illustrated in FIG. 13, a plurality of individual first-order graphene (or graphene-based) threads or fibers 150, in turn, may be woven or spun to form a second embodiment of a second-order graphene (or graphene-based) thread or fiber 225. Not separately illustrated, a plurality of first-order graphene (or graphene-based) threads or fibers 250 (formed using graphene ribbons 200) may also be utilized and woven or spun to form another embodiment of a second-order graphene-based thread or fiber. In addition, a combination of a plurality of first-order graphene (or graphene-based) threads or fibers 150 and first-order graphene (or graphene-based) threads or fibers 250 may also be utilized and woven or spun to form yet another embodiment of a second-order carbon nanotube or other graphene-based thread or fiber.

This process of weaving or spinning fibers, threads or strands of lower-order graphene (or graphene-based) threads or fibers 150, 175, 250, and 225 may be successively repeated to form higher or next-order “yarns” of graphene (or graphene-based) threads or fibers. This “yarn of yarns” may be constructed in numerous configurations well known to the spinning and weaving industries. FIG. 14 is a perspective view illustrating a next-order graphene (or graphene-based) thread or fiber 275 comprising multiple threads or strands of lower-order graphene (or graphene-based) threads or fibers (150, 175, 250, 225). As illustrated in FIG. 14, a plurality of individual first, second, third or (n−1)-order graphene (or graphene-based) threads or fibers (150, 175, 250, 225) are woven or spun to form a second, third, fourth or nth-order graphene (or graphene-based) thread or fiber 275.

FIG. 15 is a flow diagram illustrating a method of fabricating a graphene (or graphene-based) thread or fiber (150, 175, 250, 225, 275) with nth-order layers, twisting and chirality, and provides a useful summary. Beginning with start step 300, when graphene ribbons 200 are to be utilized, in step 305, the method deposits a plurality of graphene flakes 100 (and/or CNTs 110) in a polymer 190, using a shearing force, over a substrate 195, cures or allows to cure the plurality of graphene flakes 100 (and/or CNTs 110) in a polymer 190 on the substrate 195, and disassembles (e.g., cuts or slits) the cured plurality of graphene flakes 100 (and/or CNTs 110) in a polymer 190 on the substrate 195 to form a plurality of graphene ribbons 200, step 305. Step 305 may be omitted when CNTs 110 are utilized and are to be aligned with an electromagnetic field, rather than used in graphene ribbons 200. In step 310, the method then orients graphene ribbons 200 or CNTs 110 at a first angle on a starting strand 105, which may (or may not) be offset from the axial direction, and spins or rotates the graphene ribbons 200 or CNTs 110 around the starting strand 105, using a first twist or rotational direction. It should be noted that the starting strand 105 may be rotated, or the graphene ribbons 200 or CNTs 110 wound or spun, or both. When CNTs 110 are utilized, the CNTs 110 are then cured. When graphene ribbons 200 are utilized, the graphene ribbons 200 also may then be cured, as an option, as discussed above. In step 315, the method then orients graphene ribbons 200 or CNTs 110 at a second angle on the growing, previously wound or spun strand or fiber, which also may (or may not) be offset from the axial direction, and spins or rotates the graphene ribbons 200 or CNTs 110 around the growing, previously wound or spun strand or fiber, using a second twist or rotational direction. Again, it should be noted that the motion is relative, and the growing, previously wound or spun strand or fiber may be rotated, or the graphene ribbons 200 or CNTs 110 wound or spun, or both. When CNTs 110 are utilized, the CNTs 110 are then cured. When graphene ribbons 200 are utilized, the graphene ribbons 200 optionally also may then be cured, as discussed above.

In step 320, the method again then orients graphene ribbons 200 or CNTs 110, but at a third or next angle on the growing, previously wound or spun strand or fiber, which also may (or may not) be offset from the axial direction, and spins or rotates the graphene ribbons 200 or CNTs 110 around the growing, previously wound or spun strand or fiber, using either a first, second or next twist or rotational direction. Again, it should be noted that the motion is relative, and the growing, previously wound or spun strand or fiber may be rotated, or the graphene ribbons 200 or CNTs 110 wound or spun, or both. When CNTs 110 or graphene ribbons 200 are utilized, the CNTs 110 and/or graphene ribbons 200 optionally also may then be cured as well. When additional layers are to be added to the growing strand, step 325, the method returns to step 320 and iterates.

When a sufficient number of layers have been added to form a first-order graphene (or graphene-based) thread or fiber (150, 175, 250) in step 325, the method then weaves or spins a plurality of first, second or next-order graphene (or graphene-based) threads or fibers into a higher-order graphene (or graphene-based) thread or fiber, step 330. When additional orders or levels are to be added to the growing, higher order graphene (or graphene-based) thread or fiber, step 335, the method returns to step 330 and iterates until the desired higher-order graphene (or graphene-based) thread or fiber has been formed, and the method may end, return step 340.

By building layers of layers of graphene ribbons and/or SWCNTs, two key ends may be achieved. The first of these is that we avoid much, if not all, of the linear sliding between graphene and/or CNT walls by having multiple vectors with multiple layers involved and in play. While this means that most CNT layers never present an optimum strength vector it also means that the net tensile strength should be significantly greater than that previously reported for composite CNT threads. Secondly, the macro structures illustrated in FIGS. 13 and 14 provide the potential of employing numerous techniques that are well known to enhance the strength of the overall multi-strand and multi-yarn, woven graphene-based material.

In addition, all of these various aligned layers may be built using threads or strands of twisted or intertwined graphene ribbons 200 or CNTs 110, as composite or complex graphene ribbons 200 or CNTs 110 threads, as illustrated in FIG. 14. These threads or strands of twisted or intertwined graphene ribbons 200 or CNTs 110 (as complex graphene ribbons 200 or CNTs 110 threads) may be aligned as described above, both axially and axially offset, to form multiple graphene ribbon 200 or CNT 110 layers as described above.

Although the invention has been described with respect to specific embodiments thereof, these embodiments are merely illustrative and not restrictive of the invention. In the description herein, numerous specific details are provided, such as examples of electronic components, electronic and structural connections, materials, and structural variations, to provide a thorough understanding of embodiments of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, components, materials, parts, etc. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention. One having skill in the art will further recognize that additional or equivalent method steps may be utilized, or may be combined with other steps, or may be performed in different orders, any and all of which are within the scope of the claimed invention. In addition, the various Figures are not drawn to scale and should not be regarded as limiting.

Reference throughout this specification to “one embodiment”, “an embodiment”, or a specific “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment and not necessarily in all embodiments, and further, are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment may be combined in any suitable manner and in any suitable combination with one or more other embodiments, including the use of selected features without corresponding use of other features. In addition, many modifications may be made to adapt a particular application, situation or material to the essential scope and spirit of the present invention. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the teachings herein and are to be considered part of the spirit and scope of the present invention.

It will also be appreciated that one or more of the elements depicted in the Figures can also be implemented in a more separate or integrated manner, or even removed or rendered inoperable in certain cases, as may be useful in accordance with a particular application. Integrally formed combinations of components are also within the scope of the invention, particularly for embodiments in which a separation or combination of discrete components is unclear or indiscernible. In addition, use of the term “coupled” herein, including in its various forms such as “coupling” or “couplable”, means and includes any direct or indirect electrical, structural or magnetic coupling, connection or attachment, or adaptation or capability for such a direct or indirect electrical, structural or magnetic coupling, connection or attachment, including integrally formed components and components which are coupled via or through another component.

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

Furthermore, any signal arrows in the drawings/Figures should be considered only exemplary, and not limiting, unless otherwise specifically noted. Combinations of components of steps will also be considered within the scope of the present invention, particularly where the ability to separate or combine is unclear or foreseeable. The disjunctive term “or”, as used herein and throughout the claims that follow, is generally intended to mean “and/or”, having both conjunctive and disjunctive meanings (and is not confined to an “exclusive or” meaning), unless otherwise indicated. As used in the description herein and throughout the claims that follow, “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Also as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

The foregoing description of illustrated embodiments of the present invention, including what is described in the summary or in the abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. From the foregoing, it will be observed that numerous variations, modifications and substitutions are intended and may be effected without departing from the spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to the specific methods and apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims. 

It is claimed:
 1. A graphene-based fiber comprising: a starting strand; and a plurality of coatings of aligned graphene comprising: a first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.
 2. The graphene-based fiber of claim 1, wherein the graphene comprises at least one graphene ribbon.
 3. The graphene-based fiber of claim 2, wherein the at least one graphene ribbon comprises a plurality of aligned and overlapping graphene flakes in a polymer.
 4. The graphene-based fiber of claim 2, wherein the at least one graphene ribbon comprises a plurality of aligned and overlapping graphene flakes in a polymer and on a substrate.
 5. The graphene-based fiber of claim 2, wherein the plurality of coatings further comprise a plurality of winding layers of a plurality of the graphene ribbons.
 6. The graphene-based fiber of claim 1, wherein the graphene comprises a plurality of carbon nanotubes in a polymer.
 7. The graphene-based fiber of claim 6, wherein the carbon nanotubes further comprise a metallic chirality or a semiconducting chirality.
 8. The graphene-based fiber of claim 6, wherein the first angle is about 0°, the second angle is about 45°, and the at least one next angle comprises a third angle of about 135° and a fourth angle of about 90°.
 9. The graphene-based fiber of claim 1, wherein the starting strand comprises a metal, or a polymer, or a combination of a metal and a polymer.
 10. The graphene-based fiber of claim 1, wherein the first coating further comprises a first twist direction of the aligned graphene, the second coating further comprises a second, opposite twist direction of the aligned graphene, and the at least one next coating further comprises the first or the second twist direction of the aligned graphene.
 11. A graphene-based yarn comprising: a plurality of intertwined and twisted graphene-based fibers, each graphene-based fiber of the plurality of intertwined and twisted graphene-based fibers comprising: a starting strand; and a plurality of coatings of aligned graphene comprising: a first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.
 12. The graphene-based yarn of claim 11, wherein the graphene comprises at least one graphene ribbon.
 13. The graphene-based yarn of claim 12, wherein the at least one graphene ribbon comprises a plurality of aligned and overlapping graphene flakes in a polymer.
 14. The graphene-based yarn of claim 12, wherein the at least one graphene ribbon comprises a plurality of aligned and overlapping graphene flakes in a polymer and on a substrate.
 15. The graphene-based yarn of claim 12, wherein the plurality of coatings further comprise a plurality of winding layers of a plurality of the graphene ribbons.
 16. The graphene-based yarn of claim 11, wherein the graphene comprises a plurality of carbon nanotubes in a polymer.
 17. The graphene-based yarn of claim 16, wherein the carbon nanotubes further comprise a metallic chirality or a semiconducting chirality.
 18. The graphene-based yarn of claim 16, wherein the first angle is about 0°, the second angle is about 45°, and the at least one next angle comprises a third angle of about 135° and a fourth angle of about 90°.
 19. The graphene-based yarn of claim 11, wherein the starting strand comprises a metal, or a polymer, or a combination of a metal and a polymer.
 20. The graphene-based yarn of claim 11, wherein the first coating further comprises a first twist direction of the aligned graphene, the second coating further comprises a second, opposite twist direction of the aligned graphene, and the at least one next coating further comprises the first or the second twist direction of the aligned graphene.
 21. A method of manufacturing a graphene-based yarn, the method comprising: using a starting strand, applying first coating of aligned graphene axially offset at a first angle from an axis of the starting strand; applying a second coating of aligned graphene over the first coating and axially offset at a second angle from the axis of the starting strand; and applying at least one next coating of aligned graphene over a preceding coating and axially offset at a next angle from the axis of the starting strand.
 22. The method of manufacturing a graphene-based yarn of claim 21, wherein the graphene comprises a plurality of graphene ribbons and the application steps further comprise winding or spinning a plurality of layers of the plurality of graphene ribbons.
 23. The method of manufacturing a graphene-based yarn of claim 21, wherein each graphene ribbon of the plurality of graphene ribbons comprises a plurality of aligned and overlapping graphene flakes in a polymer.
 24. The method of manufacturing a graphene-based yarn of claim 23, further comprising: forming the plurality of graphene ribbons by applying, using a shearing force, the plurality of graphene flakes in the polymer onto a substrate.
 25. The method of manufacturing a graphene-based yarn of claim 24, further comprising: cutting the substrate having the plurality of graphene flakes in the polymer into a plurality of strips; and winding the plurality of strips onto one or more reels.
 26. The method of manufacturing a graphene-based yarn of claim 25, further comprising: removing the substrate to form the plurality of graphene ribbons; and winding or spinning the plurality of graphene ribbons.
 27. The method of manufacturing a graphene-based yarn of claim 21, wherein the graphene comprises a plurality of carbon nanotubes in a polymer.
 28. The method of manufacturing a graphene-based yarn of claim 27, wherein the application steps further comprise: orienting the carbon nanotubes using an applied electromagnetic field.
 29. The method of manufacturing a graphene-based yarn of claim 28, wherein the electromagnetic field is applied at the first angle of about 0°, the electromagnetic field is applied at the second angle of about 45°, and the electromagnetic field is applied at the least one next angle comprising a third angle of about 135° and a fourth angle of about 90°.
 30. The method of manufacturing a graphene-based yarn of claim 21, wherein the starting strand comprises a metal, or a polymer, or a combination of a metal and a polymer.
 31. The method of manufacturing a graphene-based yarn of claim 21, further comprising: applying the first coating using a first twist direction of the aligned graphene; applying the second coating using a second, opposite twist direction of the aligned graphene; and applying the at least one next coating using the first or the second twist direction of the aligned graphene.
 32. The method of manufacturing a graphene-based yarn of claim 21, further comprising: repeating the application steps to form a plurality of graphene-based fibers; twisting and intertwining the plurality of graphene-based fibers to form a plurality of next-order graphene-based fibers; and twisting and intertwining the plurality of next-order graphene-based fibers to form a graphene-based yarn.
 33. A method of manufacturing a graphene-based yarn, the method comprising: using a starting strand and a plurality of graphene ribbons, applying first coating of aligned graphene by spinning a first graphene ribbon, of the plurality of graphene ribbons, about a starting strand at a first angle axially offset from an axis of the starting strand, each graphene ribbon of the plurality of graphene ribbons comprising a plurality of aligned and overlapping graphene flakes in a polymer; applying a second coating of aligned graphene by spinning a second graphene ribbon, of the plurality of graphene ribbons, over the first coating at a second angle axially offset from an axis of the starting strand; applying at least one next coating of aligned graphene by spinning a next graphene ribbon, of the plurality of graphene ribbons, over a preceding coating at a next angle axially offset from the axis of the starting strand; repeating the application steps to form a plurality of graphene-based fibers; twisting and intertwining the plurality of graphene-based fibers to form a plurality of next-order graphene-based fibers; and twisting and intertwining the plurality of next-order graphene-based fibers to form a graphene-based yarn. 